package cn.imnaer.common.factory;

import com.alibaba.fastjson.JSON;

import java.security.MessageDigest;
import java.util.*;

/**
 * Created by Administrator on 2015/5/25.
 */
public class ListUtils {

    public static <T> List removeDuplicateWithOrder(List<T> list) {
        Set<T> set = new HashSet();
        List<T> newList = new ArrayList();
        for (Iterator iter = list.iterator(); iter.hasNext(); ) {
            T element = (T) iter.next();
            if (set.add(element))
                newList.add(element);
        }
        return newList;
    }

    public static <T> List removeDuplicateWithMD5(List<T> list) {
        Set<String> set = new HashSet();
        List<T> newList = new ArrayList();
        for (Iterator iter = list.iterator(); iter.hasNext(); ) {
            T element = (T) iter.next();
            String md5 = MD5(element);
            if (set.add(md5))
                newList.add(element);
        }
        return newList;
    }

    public final static String MD5(Object s) {
        String json = JSON.toJSONString(s);
        char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
        try {
            byte[] btInput = json.getBytes();
            // 获得MD5摘要算法的 MessageDigest 对象
            MessageDigest mdInst = MessageDigest.getInstance("MD5");
            // 使用指定的字节更新摘要
            mdInst.update(btInput);
            // 获得密文
            byte[] md = mdInst.digest();
            // 把密文转换成十六进制的字符串形式
            int j = md.length;
            char str[] = new char[j * 2];
            int k = 0;
            for (int i = 0; i < j; i++) {
                byte byte0 = md[i];
                str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                str[k++] = hexDigits[byte0 & 0xf];
            }
            return new String(str);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }

    }
}
